Authenticating hardware for manually enabling and disabling read and write protection to parts of a storage disk or disks for users

ABSTRACT

Data protection is weak with the methods currently available and there are risks of corrupting important data, including system data accidentally by users or by malicious programs. We are proposing a method for improving access protection, more particularly, protection for data on mass memories by adding a hardware that will enable or disable read or write protection to portions of mass memories for each user. The hardware supports one or more users and two or more states for each supported user. The state of the hardware is manually controlled by the users. Depending on the configuration, each hardware state corresponding to a user corresponds to disabling or enabling read or write protection to some portions of a mass memory or mass memories for that user.

BACKGROUND OF THE INVENTION

The present invention relates to controlling access for users to portions of mass memories such as hard disks, storage arrays, JBODs (Just a Bunch of Disks), RAID storage or future technologies for mass memories. We also use the word storage to refer to mass memories in this invention.

Current technologies provide protection at the file system level and a malicious program or user can get access as a privileged user and read confidential user data or corrupt user data. It requires hardware support to gain complete protection from malicious programs. Prior art technologies allow either full access or one level of hardware controlled restricted access. This level of hardware support is not sufficient to protect all users. It is possible for privileged users to corrupt data unintentionally by installing a malicious program or by manual error during full access.

We refer to the software, firmware and hardware components that control access to mass memories as storage components. The storage components are file systems, volume managers, storage stack, interface drivers, Host Bus Adapters, disk controllers, etc. File systems create a logical view of data in the form of files and directories. Some systems contain volume managers which present logical disks to its upper layer modules such as file systems. The storage stack provides access to physical disks for file systems, volume managers and users who do read or write directly to disks (raw access). Interface drivers control Host Bus Adapters (HBAs) and provide an interface for the storage stack to issue storage commands and transfer data from and to the storage. On systems that do not have a storage stack, file systems interact directly with interface drivers. The Host Bus Adapters are connected to storage array controllers or disk controllers through an interconnect mechanism such as SCSI, SAS, SATA, FC, IDE, etc. A firmware on a disk controller or the disk controller hardware controls operations on the disk in response to commands received from Host Bus Adapters. A firmware on the storage array controller or the storage array controller hardware controls operations on the array in response to commands received from Host Bus Adapters.

There are different methods for access control such as non-privileged users in UNIX or Windows operating systems who cannot access all parts of mass memories (storage). But a malicious program or user can sometimes exploit security weaknesses in an operating system, to get access as a privileged user. This will allow malicious users to gain access to critical data belonging to other users or corrupt users' data.

There is serious risk to users' data when their laptops are stolen or when someone gains access to a user's computer in the user's absence.

There is serious risk to users' data when a privileged user is malicious.

There are many methods for protecting user memories which do not require manual action for enabling and disabling protection; Such protections can be compromised by malicious programs by emulating the required software behavior.

U.S. Pat. No. 6,330,648 illustrates a method of adding protection against malicious programs using a manually controlled hardware with two states. By default the protection is enabled and has a mechanism to manually switch off the protection. This invention will not be able to provide protection for portions of storage belonging to each user, as is possible using our invention. Another drawback of the invention is that the solution cannot be used with mass memories which are already manufactured.

US Patent application 20060117156 illustrates a method of adding protection for non-volatile memories against malicious programs using a manually controlled hardware with two or more states, but only two states used for protection. One state has protection enabled and other state has protection disabled. This invention will not be able to provide protection for portions of storage belonging to each user, as is possible using our invention.

FIG. 1 shows an example of storage components that allow a process in a computer to connect to mass memories such as hard disks, storage arrays, etc. The computer 101 has an internal disk 102. The computer 101 is connected to an external disk 103, a storage array 104 and a JBOD (Just a Bunch Of Disks) 105. The user processes running on the computer interact with File System 106, Volume Manager 107, or the storage stack 108. File systems 106 interact with Volume Managers 107 and Storage Stack 108. The Volume Manager 107 interacts with Storage Stack 108. The storage stack sends disk read or disk write requests to Host Bus Adapter (HBA) through Interface Drivers 109, 110. The Interface Drivers control Host Bus Adapters (HBAs) 111, 112, 113, 114. The HBAs are connected to disk or array controllers through storage interconnects such as SCSI bus, SAS, SATA or FibreChannel network. In this example, HBA#1 111 is connected to Disk Controller 115, HBA#2 112 is connected to Disk Controller 116, HBA#3 113 is connected to Array Controller 117 and HBA#4 114 is connected to Disk Controller 118 in the JBOD 105.

Disk controllers control operations of the disk or disks connected to them. Disk firmware controls operations of disk controllers. Array controllers controls operations of disk controllers in arrays. Array controller firmware control operations of array controllers.

A computer may have one or more file systems. Some computers do not contain volume managers. Some computers may contain one or more volume managers. Some computers do not contain a storage stack.

BRIEF SUMMARY OF THE INVENTION

Mass memories include hard disk drives, storage arrays, JBODs, RAID storage, etc. It is the object of the present invention to use an authenticating hardware which supports one or more users and supports two or more states for each user to control access to portions of mass memories to which a user has access. We refer to this hardware as Authenticating Disk User Protection Hardware or ADUPHardware. It requires a manual action on the ADUPHardware to change the state of the ADUPHardware corresponding to each user. We refer to the manual action to change the state corresponding to a user on the ADUPHardware as DUPManualAction.

According to the invention, the software, firmware and hardware that implement access restrictions, check the current state of the ADUPHardware and fail each read or write operation which do not meet access restrictions permitted by the current state of the ADUPHardware corresponding to the user on whose behalf the read or write operation is initiated.

Privileged users provide users access to portions of mass memories. The configuration containing access restrictions for each user is written to an area of a mass memory to which only the privileged users have access. This area of the mass memory is protected by the ADUPHardware.

According to the invention, a configuration software allows a user or privileged users to further divide the portions of mass memory or memories to which the user has access and associate each state of the ADUPHardware corresponding to a user with disabling or enabling write or read access to portions of mass memory or memories. Preferably, only a user is allowed to configure access restrictions to portions of mass memory or memories to which that user has been given access by a privileged user or privileged users or the operating system.

The configuration software configures one or more storage components and/or new modules to disable or enable read or write access for a user to portions of a mass memory or memories depending on the state of the ADUPHardware corresponding to a user.

If storage components other than the file systems implement access restrictions, the file systems need to tag a read or write operation with the identifier of the current user of a buffer in the file system buffer cache. Other storage components may not be able identify the user on whose behalf a read or write request is initiated, without this tag. If more than one user is using a buffer in buffer cache in a file system, the accesses by different users need to be serialized so that there is only one user for a buffer at any point of time. Since only one user is associated with a buffer at any time, read or write requests can be tagged with the identifier of that user. The buffer in the buffer cache is written (flushed) to the mass memory (non-volatile storage) if it is dirty (a buffer becomes dirty when a user writes to the buffer), before the buffer is assigned to another user.

If storage components other than the file systems implement access restrictions, the ADUPHardware is not allowed to change the state corresponding to a user until all dirty buffers corresponding to the user are written to mass memory or memories.

The DUPManualAction on an ADUPHardware may be pressing one or more buttons and/or toggling one more switches and/or changing jumper positions etc., on the ADUPHardware.

The DUPManualAction causes the ADUPHardware to authenticate the user who initiated the DUPManualAction.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates different components of the storage system on a computer.

FIG. 2 illustrates an example for states of an ADUPHardware that accepts DUPManualActions and authenticates the users.

FIG. 3 illustrates an example for states of a device driver that control the ADUPHardware and a file system module which flushes dirty buffers of a user in the file system buffer cache to mass memory and removes association between the user and the buffers in the buffer cache, before sending a message containing the identifier of the user to the ADUPHardware device driver.

FIG. 4 illustrates an example for states of a module in the storage component that implements access restrictions for each user.

FIG. 5 illustrates an example of how different components interact when used with an ADUPHardware that accepts DUPManualActions and authenticates users.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 illustrates an example for different states of an ADUPHardware that is attached to a computer and accepts DUPManualActions. The ADUPHardware awaits 201 either a DUPManualAction from a user or a computer command. The ADUPHardware checks 202 the type of input, DUPManualAction or a command from computer. When a DUPManualAction is received, the ADUPHardware checks 204 whether the user and the state requested by the DUPManualAction are valid. If the user or the state is invalid, the DUPManualAction is ignored (discarded). If the user and state are valid, the user is prompted 205 for a password. If the password entered by the user is invalid 206, the ADUPHardware ignores (discards) the DUPManualAction. If the password entered by the user is valid 207, the ADUPHardware updates 207 a register readable by the computer, with the identifier of the user and interrupts 205 the computer using a hardware interrupt, such as PCI interrupt. The computer cannot write into the ADUPHardware register containing the identifier of the user. The ADUPHardware then returns to the state where it waits for a DUPManualAction or a computer command. When ADUPHardware receives a computer command 203 to change the state of the ADUPHardware corresponding to a user, the ADUPHardware changes the state of the user to the state selected through DUPManualAction by the user. Since the state requested by the user is not communicated to the computer, no malicious software can control the state of the ADUPHardware corresponding to a user. The ADUPHardware updates a register readable by the computer 203, with the state corresponding to the user. The computer cannot write into the register containing the state of ADUPHardware corresponding to a user.

Preferably, if more than one DUPManualAction is received for the same user before the state corresponding to the user is changed, the ADUPHardware will change state corresponding to the user to the state corresponding to the last authenticated DUPManualAction made by the user. Optionally, if more than one DUPManualAction is received for the same user before the state corresponding to the user is changed, the ADUPHardware will change the state corresponding to the user to the state corresponding to the first authenticated DUPManualAction made by the user after the last state change for the user. Some implementations may even change the state to one of the states corresponding to an authenticated DUPManualAction between the first manual action after the last state change and the last manual action depending on some other criteria.

The DUPManualAction on an ADUPHardware may be pressing one or more buttons and/or toggling the position of one or more switches and/or turning a wheel and/or changing one or more jumper positions and/or any other DUPManualAction supported by the ADUPHardware.

The ADUPHardware may use registers or memory locations readable by the computer to communicate the identifier of the user who initiated DUPManualAction and the current state of ADUPHardware corresponding to a user. A computer should not be allowed to write into these registers or memory locations. This improves security as a malicious software will not be able to manipulate the state of the hardware corresponding to each user.

An ADUPHardware may control one or more mass memories. There could be one or more ADUPHardwares on a computer, each controlling states corresponding to a mutually exclusive set of users. Some implementations may use more than one ADUPHardware on the same computer, each controlling states corresponding to sets of users which are not mutually exclusive, but we do not recommend such implementations.

There could be different behaviors for the ADUPHardware while accepting passwords. If password entered by a user is invalid, the ADUPHardware could again prompt the user for password and accept a new password from the user until a valid password is received or until the maximum number of password retries is reached or if the user cancels the request to reenter the password. The ADUPHardware that supports retries, will ignore (discard) DUPManualAction only if a valid password is not received even after maximum number of password retries or if the user cancels the password retry. The ADUPHardware may also prompt for a user name in addition to the password. The ADUPHardware may also prompt for a password before the state entered by the user is validated. The method used by an ADUPHardware for authenticating a user using a password is implementation specific.

The ADUPHardware may use other options for validating a user such as finger print validation, retina validation, other current and future technologies for user authentication. The ADUPHardware may also use a combination of two or more of password validation, finger print validation, retina validation, etc., for validating the user. The method used by a ADUPHardware for authenticating a user is implementation specific.

FIG. 3 illustrates an example for states of a device driver which runs on a computer and controls the ADUPHardware which accepts DUPManualActions. The ADUPHardware device driver runs 301 either when an interrupt from the ADUPHardware or a message from the file system arrives. The ADUPHardware device driver checks 302 the type of input, an interrupt or a file system message. When an interrupt is received 303, the driver sends a request to the file system to flush dirty buffers belonging to the user/s who identifier/s are present in the computer readable user registers. Only the identifiers of users who performed DUPManualActions will be present in the computer readable user registers of ADUPHardware. A buffer in the file system buffer cache is considered dirty if the user has written into the buffer. The file system flushes (writes to mass memories) 305 the dirty buffers in the file system buffer cache belonging to the user, resets the user identifier in all the buffers that were assigned to the user and then, sends a message 306 containing the user identifier, to the ADUPHardware device driver. The ADUPHardware device driver sends 304 a command to the ADUPHardware to change the state corresponding to the user.

If there are more than one file systems on a computer, the ADUPHardware device driver must send messages containing the identifier of the user to all the file systems on the computer. The ADUPHardware device driver will command ADUPHardware to change the state corresponding to a user only after all the file systems flush dirty buffers assigned to the user and resets the user identifier in all the buffers that were assigned to the user.

The ADUPHardware device driver may use one message for each user to request a file system to flush buffers corresponding to the user.

An ADUPHardware device driver may control one or more ADUPHardware. There could be one or more ADUPHardware device drivers running on a computer each controlling a mutually exclusive set of ADUPHardware.

There could be one or more storage components or new modules that implement access control according to the invention on a computer. We refer to the modules that implement access control according to the invention as DUPImplementers. When an upper layer module sends a new read or write request to the a DUPImplementer, the DUPImplementer will get the current ADUPHardware state corresponding to the user on whose behalf the read or write request was created. The DUPImplementer is configured with information on portions of mass memories and type of access (read or write) allowed or denied for each portion of mass memory, for each combination of user and state. The DUPImplementer checks the portions of mass memory or mass memories accessed by the read or write request against the configuration. If a read or write requests violates the access restrictions, the read or write request is not allowed to proceed and is returned with error. If no configuration is present for a portion of mass memory, DUPImplementers are configured either to allow or to block the read or write request that access such a portion.

FIG. 4 illustrates an example for a storage component that is a DUPImplementer. The storage component processes read or write requests 401. When a new read or write request arrives, the storage component will read or get the ADUPHardware state 402 corresponding to the user on whose behalf the read or write request was created. The storage component checks 403 whether the read or write request violates access restrictions configured corresponding to the current state of the user. If access is not allowed 404, the read or write request is returned to the upper layer with error. If the access is allowed 405 the read or write request is allowed to proceed.

A user is allowed access to portions of a mass memory or memories by privileged users. The portions of mass memories to which each user has access is not mutually exclusive. The portions of mass memories to which a user has access and the type of access is written to a portion of the mass memory to which only privileged users has access. The area of the mass memory where this configuration is stored is protected by the ADUPHardware.

A configuration software allows each user to further divide these portions of mass memory or mass memories to which the user has access. The configuration software further allows a user to enable or disable read or write access to each of these divided portions and associate the access restrictions to a state of the ADUPHardware corresponding to the user. Preferably, the access restrictions associated with each state is independent of access restrictions associated with other states of the ADUPHardware corresponding to the same user. Optionally, access restrictions are such that there are dependencies between access restrictions corresponding to some or all of the states corresponding to a user.

Preferably, the configuration corresponding to a user is written to a predefined area of the mass memory or mass memories, selected on the basis of the user identifier and write to this area is enabled for the user only on one or more states of ADUPHardware corresponding to the user. Preferably, no other user, including privileged users has write or read access to this area of the mass memory or mass memories.

FIG. 5 illustrates an example of interaction between different components in a computer 501 that implement read and write protection for each user to parts of a mass memory, using an ADUPHardware 506 508 that accepts DUPManualActions. Only components that are changed or affected by the invention are shown. The ADUPHardware 506 writes the identifier of the user in a memory location readable by the computer and interrupts the computer after a user performs DUPManualAction to change the state corresponding to the user and the user is authenticated. The ADUPHardware device driver 507 processes the interrupt and reads the identifier of the user from the ADUPHardware. The ADUPHardware device driver will send a request to the file system 504 to flush dirty buffers assigned to the user. The file system 504 goes through the list of buffers assigned to the user, writes (flushes) dirty buffers that were assigned to the user to the mass memory and removes the association between the user and the buffer. After removing the association between the user and all the buffers that were assigned to the user, the file system 504 sends a message to the ADUPHardware device driver 507. The ADUPHardware device driver sends a command to the ADUPHardware to change it's state corresponding to the user. Part of the ADUPHardware 508 is enclosed in the disk enclosure 510. In this example, the configuration software 502 configures the file system 504, the storage stack 503 and disk controller firmware 509 to implement access restrictions for users. The storage stack gets the state of the ADUPHardware corresponding to a user by reading the computer readable memory in the ADUPHardware containing states. The file system gets the state of ADUPHardware corresponding to a user through the ADUPHardware device driver, which reads the computer readable memory in the ADUPHardware containing states. The disk controller firmware 509 gets the state of the ADUPHardware by reading a memory in the ADUPHardware 506 508 containing the current state for each user using an interface within the disk enclosure. The state of the ADUPHardware corresponding to a user is used by the storage stack, the disk controller firmware and the file system to implement access restrictions for the user configured using the configuration software. The configuration software interacts with the storage stack to write the configuration to the disk 505. The configuration is read by the storage stack, the disk controller firmware, the file system and the configuration software. The file system and the configuration software interact with the storage stack to read the configuration from the disk 505. The components which are not affected by the invention such as Interface Driver, HBA, Disk Controller, etc., are not shown.

The protection provided by ADUPHardware need not be limited to mass memories alone. Other modules that implement access protections could check the current state of the ADUPardware corresponding to a user and implement access restrictions based on the current state and configuration associated with that state for the modules.

Since ADUPHardware or part of ADUPHardware can be enclosed in the same mass memory that is being protected, there is less risk to data even if the laptop of a user is stolen.

The authentication is done by ADUPHardware and a malicious software will not be able to manipulate the authentication process. 

What is claimed is:
 1. A method for implementing access protection, more particularly for protecting user data on a mass memory or mass memories by i) Using an authenticating hardware supporting one or more users and two or more states for each supported user; This hardware is referred to as Authenticating Disk User Protection Hardware or ADUPHardware. ii) The state of the ADUPHardware corresponding to a user is controlled by manual action by that user on the ADUPHardware; The manual action to change the state corresponding to a user is referred to as DUPManualAction. iii) The DUPManualAction causes the ADUPHardware to authenticate the user who performed DUPManualAction. The ADUPHardware rejecting the DUPManualAction if authentication fails. iv) Preferably, the ADUPHardware interrupting the host computer when a user attempts to change the state of the ADUPHardware by performing DUPManualAction and the user is authenticated; v) Preferably, after file systems writing dirty buffers assigned to the user to the storage and removing association between the user and buffers that were assigned to the user, the ADUPHardware device driver allowing the ADUPHardware to change the state for the user to the state requested by the user through the DUPManualAction; Where ADUPHardware device driver is the software component that controls the ADUPHardware; Where a buffer is dirty if a user has written to the buffer. vi) A user having access to one or more portions of a mass memory or mass memories; vii) The portions of a mass memory to which a user has access being further divided and access to these divided portions for the user being enabled only if the state of the ADUPHardware corresponding to the user allows such access; viii) A configuration software allowing a user or privileged users to associate one or more states of the ADUPHardware corresponding to a user with disabling or enabling write and/or read access to portions of one or more mass memories for that user; ix) The configuration software configuring one or more storage components and/or new modules to disable or enable read and/or write access for a user to portions of mass memory or mass memories depending on the state of the ADUPHardware corresponding to the user; The storage components being file systems, storage array controller firmware or hardware, disk controller firmware and hardware, storage stack, volume managers, Host Bus Adapter Interface drivers, Host Bus Adapter; A module that implements access protection based on the state of the ADUPHardware being referred to as DUPImplementer. x) Preferably, file systems tagging read or write requests to mass memories with the identifier of the current user of the buffer being written or read; Preferably, the access to each buffer in a file system buffer cache by different users are serialized and a dirty buffer is written to the storage before access is given to another user; xi) Preferably, the operating system tagging each raw disk read or write request with the user identifier of the user issuing the raw disk read or write; xii) Optionally, read or write commands from the computer to a mass memory or mass memories being tagged with the identifier of the user on whose behalf the read or write is initiated; xiii) A DUPImplementer using the identifier of the user in the read or write request and the current state of the ADUPHardware corresponding to the user to identify the parts of mass memory or mass memories to which access is restricted; The DUPImplementer comparing the part of mass memory or mass memories being accessed by read or write request and type of access, to the configured access restrictions. The storage components failing read or write requests which violate access restrictions. xiv) Preferably, there exists an ADUPHardware device driver that runs on the computer to which an ADUPHardware is connected and the ADUPHardware device driver controls the ADUPHardware.
 2. A method as claimed in (1), where the DUPManualAction on an ADUPHardware may be pressing one or more buttons and/or toggling the position of one or more switches and/or turning a wheel and/or changing one or more jumper positions and/or any other manual action accepted by the ADUPHardware.
 3. Preferably, a part of the ADUPHardware of claim (1) is enclosed in the same enclosure as the mass memory or mass memories which is/are being write or read protected by the ADUPHardware.
 4. An ADUPHardware of claim (1), could be used to control the state of one or more mass memories.
 5. Optionally, a computer using more than one ADUPHardwares of claim (1) to control access to portions of the mass memory or mass memories for the users of the computer. Preferably, each ADUPHardware on a computer manages a mutually exclusive set of users of the computer.
 6. Optionally, the ADUPHardware device driver of claim (1) polling ADUPHardware registers to check whether a user performed a DUPManualAction and the user is authenticated.
 7. A user configuring a mechanism to authenticate himself or herself on the ADUPHardware of claim (1).
 8. The mechanism for authentication of claim (7) is based on finger print and/or retina and/or password and/or user name and/or other current or future technologies for user authentication.
 9. The DUPManualAction on the ADUPHardware of claim (1) causing the ADUPHardware to authenticate the user who performed the DUPManualAction; If authentication fails, the DUPManualAction is ignored (discarded). If authentication is successful, the ADUPHardware generating an interrupt to the computer after updating a computer readable register or memory location with the identifier of the user who requested the DUPManualAction; The ADUPHardware device driver reading the user identifier, sending a message to the file systems; The file systems writing dirty buffers in the buffer cache which were assigned to the user, to the mass memory or mass memories and removing association between the user and all the buffers in the buffer cache that were assigned to the user and then sending a message to the ADUPHardware device driver. The ADUPHardware device driver sending a command to the ADUPHardware to change the state of the ADUPHardware corresponding to the user. The ADUPHardware updating a computer readable register or memory location with the new state of the ADUPHardware corresponding to the user.
 10. Where only file systems implement access protection, writing of dirty buffers of claim (9) not being required;
 11. Preferably, the ADUPHardware device driver of claim (1) or disk/array controller firmware of claim (1) or both being able to detect the state of the ADUPHardware corresponding a user.
 12. The ADUPHardware device driver of claim (1) detecting the state of the ADUPHardware of claim (1) corresponding to a user by polling the ADUPHardware or when the ADUPHardware interrupts the computer on which the ADUPHardware device driver is executing; The interrupt may be a PCI interrupt.
 13. The firmware of claim (12) detecting the state of the ADUPHardware of claim (1) corresponding to a user by polling ADUPHardware state or when the ADUPHardware of claim (1) creates an interrupt detectable by the firmware.
 14. The storage “software” components of claim (1) which are configured by configuration software of claim (1), identifying the state of the ADUPHardware of claim (1) corresponding to a user either by polling the ADUPHardware or by getting the state from the ADUPHardware device driver of claim (1) or by getting the state from another module; The storage “software” components being all storage components of claim (1) which run on the computer connected to the ADUPHardware.
 15. A method as claimed in (1), a user having access to portions of a mass memory or memories. The portions of mass memories to which each user has access is not mutually exclusive. The portions of mass memories to which a user has access and the type of access is written to a portion of the mass memory to which only privileged users have access. The area of the mass memory where this configuration is stored is protected by the ADUPHardware.
 16. The configuration software of claim (1) allowing a user or a privileged user to configure portions or areas of a mass memory or mass memories to which the user has access, to enable or disable read and/or write access for each configured portion for the user and to associate the access restrictions to the portions of a mass memory or mass memories to a state of the ADUPHardware of claim (1) corresponding to the user; Preferably, only a user is allowed to configure access restrictions for himself or herself within the portion of mass memory or mass memories to which he or she has access.
 17. Optionally, the configuration of claim (16) is such that by default all access is disabled for a user to portions of mass memory and when a portion of mass memory to which the user was granted access is configured for read and/or write access and the access is associated to an ADUPHardware state corresponding to the user, the access to the portion of mass memory gets enabled for the user while the ADUPHardware is in that state; or the configuration is such that by default all access is enabled for a user to portions of mass memory to which the user has access and when a portion of mass memory is configured to disable read and/or write access and the disabled access is associated to an ADUPHardware state corresponding to the user, the access to the portion of mass memory gets disabled for the user while the ADUPHardware is in that state.
 18. Preferably, the configuration of claim (16) corresponding to a user, is written to a predefined area of the mass memory or mass memories selected on the basis of the user identifier and write to this area is enabled for the user only on one or more states of ADUPHardware corresponding to the user. Preferably, no other user, including privileged users have write or read access to this area of the mass memory.
 19. Preferably, the configuration software of claim (16) allowing users to see which portions of a mass memory or mass memories to which each file or directory is mapped; Preferably, the portions or areas shown by the configuration software for a directory include portions of mass memory or mass memories used by subdirectories and all files in the directory and subdirectories.
 20. The portions of mass memory or memories of claim (1) on which access restrictions are configured corresponding to a state of the ADUPHardware corresponding to a user, need not be mutually exclusive to portions of mass memory or memories on which access restrictions are configured corresponding to another state of the ADUPHardware corresponding to the same user.
 21. The portions of mass memory or memories of claim (1) on which access restrictions are configured corresponding to a state of the ADUPHardware corresponding to a user need not be mutually exclusive to portions of mass memory or memories on which access restrictions are configured corresponding to a state of the ADUPHardware for a different user.
 22. The DUPImplementer of claim (1) which is configured to check access permissions, checking whether a read or a write operation requested in each read or write request to a mass memory, is permitted as per access restrictions corresponding to the current state of the ADUPHardware corresponding to the user on whose behalf the read or write request is initiated; The storage component failing the read or write operations which violates the access restrictions. More particularly, the DUPImplementer of claim (1) verifying the portions of mass memory or mass memories configured for restricting access and type of access restriction in the current state of the ADUPHardware of claim (1) for the corresponding user, against portions of mass memory or mass memories to be written or read as per each read or write request and failing read or write requests which are not permitted.
 23. If there is no entry in the configuration corresponding to a portion of mass memory or mass memories corresponding to a state of a user, all DUPImplementers of claim (1) on a computer being configured to either block or to allow read/write requests to such portions of mass memory or mass memories while the ADUPHardware is in that state.
 24. Preferably, a method as claimed in (1), the file system tagging read or write requests to mass memories with the identifier of the current user of the buffer in the file system buffer cache; If more than one user is using a buffer in the file system buffer cache, the accesses are serialized; A dirty buffer in the buffer cache is written to the mass memory before the buffer is assigned to another user; Where a dirty buffer is a buffer into which the user has written.
 25. The portions or areas of claim (1) of a mass memory may be identified using parameters like directories and files, or physical blocks or disk sectors or logical blocks or a combination of head, cylinder and sector, etc. The configuration software configuring a given parameter (such as logical block number) only on those DUPImplementers that recognizes the parameter.
 26. Preferably, the access restrictions of claim (1) associated with each state corresponding to a user being independent of access restrictions associated with other states of the ADUPHardware corresponding to the same user.
 27. Optionally, access restrictions of claim (1) associated with each ADUPHardware state corresponding to a user having dependency on access restrictions associated with one or more states of the ADUPHardware corresponding to the same user.
 28. Preferably, read or write commands to mass memories being tagged with the tag of claim (24) or a value derived from it;
 29. Optionally, the tag of claim (24) or a value derived from it being passed to a Fibre Channel mass memory using OX_ID field in a Fibre Channel read or write command.
 30. Optionally, where an array or disk controller firmware or hardware of claim (1) is a DUPImplementer and is not able to identify the user who initiated a read or write request, the array or disk controller firmware or hardware allowing a read or write request if it is permitted for any of the currently active users.
 31. Preferably, the registers or the memory locations of claim (9) containing states of an ADUPHardware is not writable by the computer.
 32. Optionally, one or more steps of claim (9) could be avoided for a ADUPHardware to change state corresponding to a user after a DUPManualAction and authentication of the user.
 33. A method as in claim (32) where ADUPHardware changes state as soon as a user enters a valid DUPManualAction and the user performing the DUPManualAction is authenticated.
 34. A method as claimed in (1), ADUPHardware could be used by any module that implements access restriction on a computer.
 35. Preferably, an ADUPHardware of claim (1) presents itself as an input/output device to a computer; More particularly, an ADUPHardware is preferably a PCI card; Optionally, an ADUPHardware is an input/output device attached directly or indirectly to the motherboard of a computer;
 36. Optionally, an ADUPHardware of claim (1) presents itself as a memory to a computer;
 37. The configuration software of claim (1) consists of one or more processes or modules.
 38. The method claimed in (1) being applicable to all types of mass memories such as storage arrays, JBODs, RAID storage, independent disks and internal disks of computers.
 39. The method claimed in (1) being used with future technologies for mass memories. 